Methods and systems for engine block thermal conductivity

Patent metadata

Field	Value
Publication number	US-10767594-B2
Application number	US-201916279261-A
Country	US
Kind code	B2
Filing date	Feb 19, 2019
Priority date	Feb 20, 2018
Publication date	Sep 8, 2020
Grant date	Sep 8, 2020

Abstract

Methods and systems are provided for coatings of a portion of an engine block shaping a combustion chamber. In one example, the engine block includes a first coating with a thermal conductivity higher than a conductivity of the engine block arranged in an upper region of the combustion chamber and a second coating with a thermal conductivity lower than the conductivity of the engine block arranged in a lower region of the combustion chamber, and where the second coating touches the first coating.

First claim

The invention claimed is:

1. An engine block comprising:
a first coating arranged on interior surfaces of a cylinder near a top-dead center position of a piston and a second coating arranged on the interior surfaces near a bottom-dead center position of the piston, the first coating comprising a hypereutectic aluminum-silicon alloy and the second coating comprising an iron-based alloy with a thermal conductivity lower than a thermal conductivity of the first coating and a thermal conductivity of the interior surfaces.

2. The engine block of claim 1 , wherein the interior surfaces comprise aluminum or an aluminum alloy, and where the thermal conductivity of the interior surfaces is less than the thermal conductivity of the first coating is and greater than the thermal conductivity of the second coating.

3. The engine block of claim 1 , wherein a silicon content of the first coating is greater than 10%.

4. The engine block of claim 1 , wherein the second coating comprises a portion with an iron-carbon alloy comprising between 0.5 to 2% carbon.

5. The engine block of claim 1 , wherein the second coating comprises between 20 to 50% iron, and where the iron-based alloy further comprises one or more of chromium, tungsten, niobium, boron, molybdenum, manganese, and carbon.

6. The engine block of claim 1 , wherein the first coating is arranged on the interior surfaces of the cylinder at the top-dead center position and extends up to an upper threshold position equal to a 50° rotational angle value of the piston.

7. The engine block of claim 6 , wherein the second coating is arranged on the interior surfaces of the cylinder at the bottom-dead center position and extends to at least an extreme end of the first coating.

8. The engine block of claim 1 , wherein the second coating overlaps with the first coating, and where the extreme end of the first coating comprises a wave-like shape.

9. The engine block of claim 1 , wherein the second coating comprises a conically shaped widening, wherein the conically shaped widening widens in a direction toward the bottom-dead center position.

10. The engine block of claim 1 , wherein the first coating is arranged on the interior surfaces via a laser cladding, and where silicon powder is injected during the laser cladding, and where the first coating comprises between 30 to 40% silicon.

11. A system comprising:
a combustion chamber shaped between surfaces of an engine head, an engine block, and a piston, the piston shaped to oscillate along a longitudinal axis passing through its center;
a first coating arranged on surfaces of the engine block corresponding to interior surfaces of the combustion chamber adjacent to the engine head and a top-dead center position of the piston, and where a first coating thermal conductivity is higher than an interior surfaces thermal conductivity, and where the first coating is an aluminum-silicon alloy comprising greater than 12% silicon; and
a second coating arranged on surfaces of the engine block corresponding to interior surfaces of the combustion chamber distal to the engine head and adjacent to a bottom-dead center position of the piston, and where a second coating thermal conductivity is lower than the interior surfaces thermal conductivity, and where the second coating is an iron-alloy with a nanocomposite material.

12. The system of claim 11 , wherein the first coating comprises a wave-shape at an extreme end where it touches the second coating, and where the second coating overlaps with the first coating and completely covers the wave-shape.

13. The system of claim 11 , wherein the first coating is arranged on the interior surfaces of the combustion chamber via a laser cladding, and where the second coating is arranged on the interior surfaces of the combustion chamber via a thermal spray after the first coating.

14. The system of claim 11 , wherein the second coating is arranged on the interior surfaces of the combustion chamber via a thermal spray, and where the first coating is arranged on interior surfaces of the combustion chamber via a laser cladding after the second coating, and where a weld-metallurgical bond is arranged between overlapping portions of the first coating and the second coating.

15. The system of claim 11 , wherein the first coating is arranged from the top-dead center position to an area between a lower threshold and an upper threshold, wherein the lower threshold is equal to a 5° rotational angle value of the piston, and where the upper threshold is equal to a 50° rotational angle value of the piston, and where the second coating extends from an extreme end of the first coating to the bottom-dead center position, and where the second coating touches the extreme end of the first coating.

16. A method comprising:
applying a first coating with a first thermal conductivity to interior surfaces of an upper region of a combustion chamber, wherein the first coating is an aluminum-silicon alloy comprising greater than or equal to 12% silicon; and
applying a second coating with a second thermal conductivity less than the first thermal conductivity to interior surfaces of a lower region of the combustion chamber during a cooling process of the first coating to generate a weld-metallurgical bond therebetween; wherein
the upper region extends from a top of a portion of the combustion chamber shaped in an engine block down to a portion of the combustion chamber equal to between 20 to 40% of its total length, and where the lower region extends from the upper region to a bottom of a portion of the combustion chamber shaped in the engine block.

17. The method of claim 16 , wherein applying the first coating comprises laser cladding welding the first coating.

18. The method of claim 17 , further comprising injecting silicon powder during the applying of the first coating to increase a silicon content of the first coating to between 30 to 40%.

19. The method of claim 16 , further comprising honing the first and second coatings to a desired thickness, and where a first coating desired thickness is less than or equal to 250 μm and where a second coating desired thickness is less than or equal to 750 μm.

20. The method of claim 19 , wherein the second coating comprising a conically shaped widening increasing in width from the upper region to the bottom, and where the second coating comprises an iron-alloy with a microcrystalline structure and where the first coating comprising an aluminum-silicon alloy.

Assignees

• Ford Global Tech Llc

Inventors

• Weber Carsten
• Turner Paul
• Morawitz Urban
• Verpoort Clemens Maria

Classifications

• C23C28/021

  including at least one metal alloy layer · CPC title

• C23C26/00

  Coating not provided for in groups C23C2/00 - C23C24/00 · CPC title

• F02F1/18

  Other cylinders · CPC title

• F02F1/004 Primary

  Cylinder liners (F02F1/08, F02F1/16 take precedence) · CPC title

• F02F1/08

  running-liner and cooling-part of cylinder being different parts or of different material · CPC title